Joshua Roberts / Reuters

“What is chicken?” asked the great Judge Henry Friendly in Frigaliment Importing Co. v. B.N.S. International Sales Corp., a case read by every first-year law student. Is it “a young chicken, suitable for broiling and frying” or rather “any bird of that genus that meets contract specifications on weight and quality”? And do you care? Law students do not, but the clients did—at stake was a tidy sum of money.

The stakes are higher in a Supreme Court case to be heard next Wednesday. Nielsen v. Preap may determine whether thousands of longtime residents of the U.S. face indefinite detention without a hearing. And as in Frigaliment, the heart of the dispute is an everyday word: when. Does it mean “any time the government decides after a stated event, whether days, weeks, or years later” or “immediately upon the happening of the event”?

Nielsen is a class action brought by a group of immigrants in the Ninth Circuit who have been or are being detained under 8 U.S.C. § 1226, a provision of the Immigration and Nationality Act. That section authorizes federal authorities to detain any alien who may be subject to “removal,” the technical term for deportation. The term covers a lot of immigrants—border crossers arrested after entering the U.S. illegally, tourists or students who have overstayed their visas, and lawful permanent residents who have committed certain crimes.

The statute creates two classes of “removable” aliens: first, ordinary detainees who haven’t committed crimes but are facing removal on other grounds and, second, “criminal aliens” facing removal because of criminal convictions.

Once ordinary aliens are detained for removal, they face three different legal tests. First will be a “bond hearing,” at which they can try to convince an immigration judge that they can be safely released, and will show up for their deportation hearing. They can provide evidence of their community, and family members can attend to give their support. If they get bond, they can go back to their lives until their next hearing. Next, whether or not they get bond, they receive a “removal hearing,” at which they can try to show that they are not “removable” after all. If they win there, they are free to go. But even if they fail in that effort, they can still try to show that they are eligible for what is called “cancellation of removal”—for example, because they have been lawfully present in the U.S. for years and have family ties here, or because deportation would subject them to danger in their country of origin. If the immigrant can prove that claim, immigration authorities have the discretion to allow him or her to remain and “adjust” to legal status.

But go back to the beginning—the bond hearing. Some “criminal aliens” have been convicted of certain specified statutory crimes (such as drug or firearms offenses, sex offenses, terrorism or espionage, or crimes of “moral turpitude”). For this “criminal alien” group, the statute says that “when the alien is released” from imprisonment, the government “shall take [him or her] into custody.” These immigrants get no bond hearing; they must be held in detention until their cases are resolved. They can still challenge removal, and they can still ask for cancellation, but they must remain behind bars for the months or even years those proceedings can take.

This is the issue in Nielsen v. Preap: It is not whether authorities can detain these aliens; they can. But does the statute really deny bond hearings to all of them—longtime residents of the U.S. who were convicted of minor offenses five, 10, 15, or more years ago? What if a person has long ago been released and has returned to a community, established a family and put down roots, and lived a blameless life since that brush with the law? In other words, what if the immigrant would otherwise be a prime candidate for bond?

These aliens can be detained and deported. There is no question that ICE agents can show up at their homes, arrest them, and hold them for removal proceedings. But does the when language mean they don’t get a bond hearing? If a noncitizen has left prison and established a new life, did Congress, in writing the statute, really mean to deny that person the chance to show an immigration court that he or she will show up for a removal hearing, the way other “noncriminal” aliens can?

And that’s where the meaning of the word when comes in.

This is a class-action case on behalf of immigrants, many of whom served or are serving sentences, or even probation, for minor offenses. One of the lead plaintiffs, Mony Preap, was born to Cambodian parents in a refugee camp; he has lived lawfully in the U.S. since 1981. In 2006, he was convicted on two misdemeanor counts of possessing marijuana—an offense that would have subjected him to mandatory detention. However, immigration authorities did not arrest him then. Instead, he returned to his community and was convicted of battery—which does not trigger the mandatory-detention statute. Immigration and Customs Enforcement at that point took him to a detention center, and he was denied a bond hearing. He was eventually able to show an immigration judge that he was eligible for “cancellation,” and so he has been released.

Another plaintiff, Eduardo Vega Padilla, arrived as a toddler and has been a lawful resident for 52 years; his six grandchildren are all U.S. citizens. He was convicted of controlled-substance offenses in 1997 and 1999, and placed on probation; while he was serving that sentence, he was convicted of possessing an unloaded pistol, then released in 2002. In 2013, ICE agents arrested him at his home. Because of the drug offense, ICE denied him a bond hearing until a district court ordered them to provide one—at which point he won release.

Representing all immigrants arrested under similar circumstances, the plaintiffs argue that if ICE wants to detain an immigrant without hope of bail, it must detain him or her at the moment of release; any other reading of the when in the statute, they say, allows authorities to wait years, and then detain immigrants long after they have successfully returned to their lives. Congress cannot have intended that.

That reading is something like when in this sentence: “When you have completed the quiz, turn in your paper and pencil, and exit quietly.” The government’s reading might seem more like this chestnut: “You’ll understand when you’re older.”

The government argues that Congress, concerned about crimes committed by undocumented aliens, meant to require bondless detention of all “criminal aliens,” full stop. The when clause doesn’t limit this requirement to some subset of “criminal aliens,” it argues; the timing of detention is irrelevant. The brief states:

If somebody gave you a two-sentence shopping list saying “(1) Pick up milk, eggs, and cheese when the store opens”: and (2) “refrigerate the groceries described above,” no sensible person would believe that, if you did not pick up the milk, eggs, or cheese until long after the store first opened, you could leave them out on the counter rather than put them in the refrigerator.

The government points out that four other circuits have rejected the plaintiffs’ reading, permitting detention without bond of even those arrested long after their release. Those opinions, however, do not all agree on how to analyze the statutory language. The First Circuit also considered the issue en banc—meaning in a review by all the judges—and split evenly. That allowed to stand a lower-court order requiring bond hearings. In that case, Judge David Barron, a former Harvard professor, wrote an opinion for himself and two other judges supporting bond hearings. That brief thoroughly discusses the linguistic issue, including footnotes like:

According to linguists, ‘probably the most important thing to understand’ about antecedents ‘is that [antecedents] are not the elements in the text but are those suggested by it, those concepts being evoked or constructed in the reader’s mind.’ Bonnie Lynn Nash-Webber, Anaphora: A Cross-Disciplinary Survey 6 (Apr. 1977).

I loved that opinion, but I am, well, a nerd. Non-nerds should skip it and simply bear in mind that the Court’s decision will subject many immigrants to mandatory detention who might otherwise qualify for temporary freedom.

Michael Tan, the ACLU lawyer who is lead counsel for the plaintiffs, told me that hard numbers are hard to come by—but that he estimates that in the Ninth Circuit alone, there may be more than 1,000 immigrants who will be eligible for hearings if the Supreme Court adopts their reading of when. (How many would actually be released after those hearings is a different story.)

If the plaintiffs win, however, aliens all over the country will be affected. Tan says that could mean a “few thousand immigrants nationwide would receive bond hearings.”

The government’s brief argues that a decision for Preap would impact its ability to hold dangerous criminal aliens: “[Immigration agents] cannot always be standing at the jailhouse door waiting to take custody of every criminal alien at the very moment he is released,” it says. But a victory for the plaintiffs would not deprive Homeland Security of the power to detain aliens it arrests after release; it would mean only that those aliens would have a chance to show that, since release, they have put down roots and will not flee. In that hearing, the burden of proof is on the alien, not the government. The statistics show that most aliens released on bond do appear for their hearings.

Last term, the Court punted in an immigration-detention case, Jennings v. Rodriguez. The issue there was whether all aliens, no matter when arrested, were entitled to bond hearings. In a 5–3 compromise opinion, the Court decided that the same statute did mandate bondless detention for at least some “criminal aliens”—but it remanded the case to the Ninth Circuit for a decision on whether that draconian rule made the statute unconstitutional. The opinion, by Justice Samuel Alito, was chilly toward aliens and solicitous of Homeland Security. Nielsen v. Preap will be heard by eight of the justices who decided Jennings—joined by the newly confirmed Justice Brett Kavanaugh.

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